Updated October 29, 2026.

Part of the Oct 28 HHS policy.

What is TB-500?

TB-500 is a synthetic fragment of thymosin beta-4, a peptide found naturally in almost every cell in your body.

Thymosin beta-4 plays a role in how cells move and organize during repair, which is why TB-500 is so often paired with BPC-157 in recovery-focused plans.

What the research is looking at

TB-500 is being studied for its role in:

  • Blood flow and new blood vessel formation
  • Tissue repair
  • Inflammation balance
  • Recovery and mobility

FDA's scientists noted that human data is still limited.

Where TB-500 stands with FDA

On October 28, 2026, HHS announced it does not intend to take enforcement action against state-licensed compounding pharmacies that compound TB-500, while FDA goes through the formal rulemaking process to decide whether to add it to the official 503A compounding list.

This is not FDA approval. TB-500 is not an FDA-approved drug.

It's an interim policy that HHS says it may revisit at any time, for example if a safety or quality issue comes up. Formal rulemaking is expected to take about 12 to 24 months.

Read the full FDA update

Under the HHS policy, TB-500 (acetate) is covered for subcutaneous and intramuscular use, as a single-peptide product.

Good to know

  • Thymosin beta-4 and its fragments, including TB-500, are on the WADA prohibited list. If you're tested in your sport, check before starting.
  • TB-500 is also one half of our Wolverine Blend.

How it works at Optimize Hormone

Optimize Hormone offers these prescription peptides from an FDA-inspected 503(a) pharmacy in the US, with full testing reports, delivered directly to your home.

Our approach to peptide therapy is personalized and provider-guided, designed to support recovery, performance, longevity and overall wellness.

  • Bloodwork membership not required for peptides.
  • Complete your online intake, or book a free consultation if you'd like to talk it through first.
  • Our provider reviews your health history and goals and determines whether TB-500 is appropriate for you.
  • If prescribed, your medication ships to your door with all necessary supplies, plus personalized dosing and instructions from your licensed provider.

Book your free consultation

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Educational information only, not medical advice. Compounded medications are not FDA-approved, which means FDA does not review their safety, effectiveness or quality before they are dispensed. Our provider determines whether any medication is appropriate for you. Regulatory information is current as of October 29, 2026 and may change. Prescriptions are filled by a state-licensed 503(a) compounding pharmacy in the US.